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Gravitational Doppler
Sci astro added, sci.math and comp.ai.p.. removed.
Lester Zick wrote: On 24 Jul 2006 09:11:21 -0700, wrote: Lester Zick wrote: Gravitational Doppler ~v~~ We are well aware of gravitational lensing but there is another EM analog associated with Newtonian universal gravitation as well: gravitational doppler. In other words with latency extensions to Newtonian universal gravitation we can explain planetary orbital perihelion anomalies and calculate the Pioneer anomaly in simple, direct terms. To do this we only need to calculate Pioneer's velocity away from the sun as a fraction of the speed of light and recognize that the effect of the sun's gravitation will increase in proportion: (Numbers used here were drawn from a column 1 article in the L. A. Times of 12/21/2004 and are not exact) Yearly distance traveled by Pioneer = 219,000,000 miles Yearly discrepancy in distance = 8,000 miles Ratio = ~ 27,375 speed of light = 186,289 miles per second Yearly distance traveled by light in one year= 186,289 mi/sec x 1440 min/day x 60 sec/min x 365 days/yr Divided by yearly distance traveled by Pioneer Ratio = ~ 26,825 A difference between the two ratios of 2% (27375 - 26,825 / 27,375) QED ~v~~ I can't see any relation between the calculation above and the description below. Perhaps it wasn't as clear as I had hoped. I made an error in my calculation, I used km/s in one place and m/s in another, doh! That knocks a factor of 1000 out in the results so our numbers are much closer, sorry. At the time of publication Pioneer was traveling about 7 miles/sec (actually 6.9444 . . . according to my calculation. In January 1987 the speed was 7.984026 mile/sec In December 1994 the speed was 7.706486 mile/sec That number in relation to the speed of light produces a ratio around 27,000 The ratios above are 23332 and 24172 respectively so that's not bad given that you are using approximate speeds. or within 2% of the discrepancy in distance traveled. In other words the discrepancy in expected yearly distance of travel would be proportional to the ratio between the speed of travel and the speed of light taken as the speed of propagation for gravity. Now that's where we diverge. What do you mean by "the discrepancy in expected yearly distance of travel"? The anomaly is a constant acceleration so the discrepancy is speed increases each year and the discrepancy in distance is quadratic. Ordinarily we consider doppler primarily in terms of repulsive forces, radiation, sound, etc. No, ordinarily we think of Doppler as a change of frequency and not related to forces. Light is an exception since radiation pressure depends on frequency, but that's not too significant at the moment However doppler also operates in analogous terms for attractive forces such as gravitation, electrostatic, and magnetic forces except that effects are reversed. Consider two strong magnets on a table. They remain stationary as long as first order friction effects exceed magnetic attraction between them. However if one magnet is dragged away from the other at high speed the other magnet experiences an excess force of attraction causing it to move toward the moving magnet. Really? I haven't worked out the details but I haven't seen that effect. I suppose it might result from induction. The effect is pure doppler except in the case of attractive forces an increase in speed away increases wavelengths and strength of the attractive force. The same is true of all attractive forces operating through space. Increasing wavelengths of attractive forces increases the degree of attraction and decreasing wavelengths of attractive forces decreases attraction by amounts proportional to increases or decreases of speed in relation to the speed of propagation for the force, the speed of light. Imagine for a moment that the locus of attraction in the solar system suddenly moves. Do you imagine that planetary orbits would be unaffected? Changes in gravity are expected to propagate at c. If the sun suddenly moved away from the earth the earth would be tugged toward it by an amount linearly related to the speed of movement of the sun and having nothing to do with gravitational constants. No, it would be unaffected for about 500s then the force would start to diminish. I don't think you are talking of gravito-magnetic effects which would be very small if they existed in that configuration. And conversely if the sun suddenly moved toward the earth its attraction would be lessened by a comparable amount and the orbit of the earth extended as a result. Now in approaching the Pioneer anomaly all I did was show that the ratio between distance of expected travel and discrepancy in expected travel were almost identical (witnin 2%) of the speed of travel and the speed of light. I extrapolated the magnitudes over a year to conserve precision. In other words if we call the expected distance of travel D and the discrepancy in expected travel d, the speed of travel v and the speed of light c we find that D/d is almost exactly c/v. The problem there is that the discrepancy is a constant acceleration a_P hence d = 1/2 * a_P * t^2 while the speed is almost constant so D ~ v * t then D/d ~ (2 * v) / (a_P * t) snip Mercury I hope this explanation is a little clearer. Yes, it is better and hopefully my consternation is a little clearer too. v/c is constant and D increases linearly with time whereas d increases with the square of time because it is a constant acceleration. In other words Pioneer travels about 7 miles per second away from the sun and in doing so gravitation waves lengthen and their attractive intensity is experienced longer in each wave. (In this respect unlike repulsive waves like EM radiation, the effect of attraction increases in gravitation with longer waves and decreases with shorter waves.) And conversely the attraction of gravitation should decrease as the sun is approached. If it is increased when the craft is moving away from the Sun and decreased when moving towards, it is first order and the Sun's gravitational effect would be changed from a = GM/r^2 to a' = (1+v/c) * GM/r^2 The discrepancy would be a_P = v/c * GM/r^2 For Pioneer 10 that varies from 1.58*10^-13 m/s^2 at 40AU down to 6.77*10^-14 m/s^2 at 60AU. The anomaly is actually 8.74*10^-10 m/s^2 so your prediction is too small by a factor of about 5000 at the start and more than double that by the end of the period they studied. Your Clearly the Pioneer Anomaly is caused by what I call gravitational doppler. .... Not even close. Well, George, I'm not sure what the problem is here. Most of it was mine. I show the expected discrepancy in distance traveled by Pioneer is proportional to c/v and you tell me it isn't because you insist on relating it to gravitational acceleration instead of the actual anomaly. The discrepancy is in net distance traveled versus expected distance traveled and not in gravitational acceleration. I was trying to understand your description and guessed badly. You said the extra force was related to the speed ratio and since that is dimensionless you need to multiply it by an acceleration or speed to get it into dynamical units. The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. George |
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Gravitational Doppler
I'll coalesce my replies:
"Lester Zick" wrote in message ... On Mon, 24 Jul 2006 22:38:04 +0100, "George Dishman" wrote: "Lester Zick" wrote in message . .. On 24 Jul 2006 05:20:36 -0700, wrote: .... Lester, the original Anderson paper is he http://www.arxiv.org/abs/gr-qc/0104064 That's the abstract, there should be a PDF option on the page that gives you the full document (I have some preferences set so I get PDF by default, it might be an option for you). I haven't seen the article but you said "Yearly discrepancy in distance = 8,000 miles" so in 8 years that means a total of 64,000 miles, doesn't it? Anyway my point is that there isn't a consistent value for "yearly discrepancy in distance" it is different every year. Sure there would be with any acceleration. My point here is that Pioneer is so far out that acceleration is probably close to zero over the course of a year so I took the liberty of assuming it so. Maybe that's the 2% error factor. The acceleration due to the Sun fell from 3.69*10^-6 m/s^2 to 1.64*10^-6^2 m/s over the period from the beginning of 1987 to the end of 1994. During that time the anomaly consisted of an additional constant acceleration of 8.74*10^-10 m/s^2. In any event The Times takes pains to be accurate and they were dealing directly with the discoverer of the anomaly at JPL so I'm confindent they got their figures from him all the while acknowledging the figures as approximate. I too have discussed the anomaly with one of the authors and Craig Markwardt repeated the calculations using different software and got the same result. His paper is he http://www.arxiv.org/abs/gr-qc/0208046 I get a mention in the acknowledgements so I know what I'm talking about too. The speed of the craft fell from 7.98 miles/sec to 7.71 miles/sec over the period while the anomaly increased linearly from 0 to about 100 mm/s in the same period (I'm not going to turn 100 mm/s into miles per second!) Well here I can only fall back on the numbers in the article. I just checked them and they were an expectation D of 219 million miles of travel in a particular year, a discrepancy d of 8,000 miles in the same year which translate into ratios of d/D=v/c to within 2%. That's all I ever intended by "calculating the Pioneer anomaly". It was just showing the source of the anomaly in mechanical terms. I wouldn't expect the same anomaly would have been present throughout the journey but apparently it was during composition of the article. You are welcome to check the article and the numbers of course. I guess you mean this http://tinyurl.com/rfotm the full article costs and I'm not paying when I can get the original article for free. I just calculated the expected discrepancy in distance for 2004 and it's about 9000 miles so not far off. Expressing the effect as a function of acceleration and the gravitational constant lies outside my interest because the mechanical principle of interest is gravitational doppler. The fact is that gravitational "constants" are actually not constant at all and vary considerably in magnitude and direction according to ordinary linear doppler effects of speed in relation to the speed of light. That's why I delayed calculation of the effect for a year. Everyone appeared to be looking at a discrepancy in the gravitational constant for explanation of the effect when it really has nothing to do with that. It's just the doppler principle applied to gravitation in purely mechanical terms of speed in relation to the speed of light. Straightforward Newtonian gravitation adjusted for latency of propagation. "Latency of propagation" gives an entirely different result. I get latency values of 2.1 to 7.2s over the same period. Perhaps you could explain how you get from latency to the speed related value. Well I'm not sure what you mean by latency values here, George. If there is a delay due to propagation then the acceleration felt by the craft would be GM/r^2 but for r at a slightly earlier time. The anomaly is a_P so the total acceleration is: a = GM/r^2 + a_P Let R be a reduced radius such that: a = GM/r^2 + a_P = GM/R^2 then the latency time is the time it took for the effect of gravity to get from R where the value was produced to r where the craft had reached when it was affected. The latency as a time t_lat is then: t_lat = (r - R) / v The numbers as I said range from about 2 to 7 seconds. What I have always meant by the term "latency" is taking into account the latency of propagation associated with gravitation in relation to the velocity of objects affected by gravitation as well as the effect of rotational dynamics of bodies such as the sun and its impact on its eccentric locus of gravitational attraction. So I don't quite know how to give you any specific latency numbers except as v/c fractions of velocity in relation to c at any given point in a trajectory. You can see my method above. --:-- "Lester Zick" wrote in message news On 24 Jul 2006 13:51:41 -0700, wrote: Sci astro added, sci.math and comp.ai.p.. removed. Lester Zick wrote: On 24 Jul 2006 09:11:21 -0700, wrote: .... At the time of publication Pioneer was traveling about 7 miles/sec (actually 6.9444 . . . according to my calculation. In January 1987 the speed was 7.984026 mile/sec In December 1994 the speed was 7.706486 mile/sec Interesting. The article was dated 12/21/04 so my calculation of v seems right in line. It was about 7.529 miles/sec in the middle of 2004. That number in relation to the speed of light produces a ratio around 27,000 The ratios above are 23332 and 24172 respectively so that's not bad given that you are using approximate speeds. Yeah. But I think you have to realize that I wasn't using speeds directly as there were no speeds indicated in the article (alas!). All I had to go on were the yearly expectation of distance D for some year and the yearly discrepancy d presumably for the same year. OK, that was reasonable given what you had to go on. Hopefully the full paper above will give you a much better picture. Unfortunately what you couldn't know was that the quoted discrepancy is only valid for that year. .... Now that's where we diverge. What do you mean by "the discrepancy in expected yearly distance of travel"? That's roughly the way the numbers were described in the article. As noted just above I didn't use velocity numbers directly but expected distance D and discrepancy in distance d in one year's travel because that's what the article gave. The anomaly is a constant acceleration so the discrepancy is speed increases each year and the discrepancy in distance is quadratic. Disagree. Especially at distances where little or no significant acceleration occurs. Statement of fact, sorry, the Times article obviously didn't make that clear. snip background Imagine for a moment that the locus of attraction in the solar system suddenly moves. Do you imagine that planetary orbits would be unaffected? Changes in gravity are expected to propagate at c. Of course. And I have no doubt the basic force itself does too. At least that's what I would infer from my calculation of the Pioneer anomaly as well as the idea that gravitation propagates in waves. If the sun suddenly moved away from the earth the earth would be tugged toward it by an amount linearly related to the speed of movement of the sun and having nothing to do with gravitational constants. No, it would be unaffected for about 500s then the force would start to diminish. I don't think you are talking of gravito-magnetic effects which would be very small if they existed in that configuration. Well of course there is the propagation delay to consider but the effect itself would still occur. But whether you're talking attraction increase or decrease would depend on the direction of motion. OK, that should give a bit of background to why I calculated your "latency" they way I did. It's not well thought out but was the only way I could imagine to approach your use of the term as "latency" normally means a time delay. Now in approaching the Pioneer anomaly all I did was show that the ratio between distance of expected travel and discrepancy in expected travel were almost identical (witnin 2%) of the speed of travel and the speed of light. I extrapolated the magnitudes over a year to conserve precision. In other words if we call the expected distance of travel D and the discrepancy in expected travel d, the speed of travel v and the speed of light c we find that D/d is almost exactly c/v. The problem there is that the discrepancy is a constant acceleration a_P hence d = 1/2 * a_P * t^2 And I strongly (but politely) disagree because the anomaly is between actual distance traveled versus expected distance traveled. Everything else represents potential assumptions and interpretations used to explain the source of discrepancy but the actual discrepancy itself is actual distance traveled versus expected distance traveled. No, what is measured for Pioneer is the frequency of the telemetry carrier. Doppler on that gives a speed and there is an error in the speed versus the best fit model which increases linearly with time. Look at Figure 8 on page 20 of the Anderson paper. http://www.arxiv.org/abs/gr-qc/0104064 while the speed is almost constant so D ~ v * t then D/d ~ (2 * v) / (a_P * t) snip Mercury I hope this explanation is a little clearer. Yes, it is better and hopefully my consternation is a little clearer too. v/c is constant and D increases linearly with time whereas d increases with the square of time because it is a constant acceleration. In the absence of significant acceleration v/c is constant and both D and d are linear functions of time and constant over one year periods. Unfortunately the anomaly itself is a constant acceleration and about 3000 times smaller than the gravitational acceleration of the Sun. That said, even the latter is so small it only changed the craft speed by 3.5% in 8 years so you can take the speed as being almost constant but you then have to process accelerations. I was trying to understand your description and guessed badly. You said the extra force was related to the speed ratio and since that is dimensionless you need to multiply it by an acceleration or speed to get it into dynamical units. Well you know I'd like to stay away from the term "force" in the present context because I can't describe how this force translates into a constant change in velocity at present. Easy, the anomaly is a constant acceleration a_P. The force is simply a_P / M and the mass of the craft is discussed in the paper, round about 241 kg. As for translation: constant acceleration == linear change of speed though the discovery process uses that the other way round. All I can actually claim is to have calculated a constant ratio v/c reflective of the anomaly to within 2% and speculate it is a linear doppler ratio indicating a relative lenghening in gravitational wavelenghts. The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. All I have right now is a linear ratio v/c which correlates with the Pioneer anomaly almost exactly. The ratio almost certainly reflects a first order doppler effect in terms of the propagation of gravitation but exactly how this ratio translates into a constant change in v is not apparent at least to me. Perhaps there are others more familiar with longitudinal doppler effects who could comment. However it is enough for the present that we can calculate the effect directly. As noted in a collateral post I never suggested I can calculate variances in gravitational constants directly as a function of velocity. But I'm convinced the effect itself is real and the calculations reflect that. Unfortunately your value only matches for that one year, for the year 1987 the discrepancy d was only about 245 miles. It is a strange coincidence but there are a lot of those in this topic. No doubt you will come across more if you continue to study the anomaly, but please at least skim Anderson's paper first, you will save yourself a lot of effort. If you can read that and Markwardt's paper in more detail you will find them fascinating insights into how the data was processed and how much has been ruled out. George |
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Gravitational Doppler
wrote:
Sci astro added, sci.math and comp.ai.p.. removed. Lester Zick wrote: On 24 Jul 2006 09:11:21 -0700, wrote: Lester Zick wrote: Gravitational Doppler ~v~~ We are well aware of gravitational lensing but there is another EM analog associated with Newtonian universal gravitation as well: gravitational doppler. In other words with latency extensions to Newtonian universal gravitation we can explain planetary orbital perihelion anomalies and calculate the Pioneer anomaly in simple, direct terms. To do this we only need to calculate Pioneer's velocity away from the sun as a fraction of the speed of light and recognize that the effect of the sun's gravitation will increase in proportion: (Numbers used here were drawn from a column 1 article in the L. A. Times of 12/21/2004 and are not exact) Yearly distance traveled by Pioneer = 219,000,000 miles Yearly discrepancy in distance = 8,000 miles Ratio = ~ 27,375 speed of light = 186,289 miles per second Yearly distance traveled by light in one year= 186,289 mi/sec x 1440 min/day x 60 sec/min x 365 days/yr Divided by yearly distance traveled by Pioneer Ratio = ~ 26,825 A difference between the two ratios of 2% (27375 - 26,825 / 27,375) QED ~v~~ I can't see any relation between the calculation above and the description below. Perhaps it wasn't as clear as I had hoped. I made an error in my calculation, I used km/s in one place and m/s in another, doh! That knocks a factor of 1000 out in the results so our numbers are much closer, sorry. At the time of publication Pioneer was traveling about 7 miles/sec (actually 6.9444 . . . according to my calculation. In January 1987 the speed was 7.984026 mile/sec In December 1994 the speed was 7.706486 mile/sec That number in relation to the speed of light produces a ratio around 27,000 The ratios above are 23332 and 24172 respectively so that's not bad given that you are using approximate speeds. or within 2% of the discrepancy in distance traveled. In other words the discrepancy in expected yearly distance of travel would be proportional to the ratio between the speed of travel and the speed of light taken as the speed of propagation for gravity. Now that's where we diverge. What do you mean by "the discrepancy in expected yearly distance of travel"? The anomaly is a constant acceleration so the discrepancy is speed increases each year and the discrepancy in distance is quadratic. Ordinarily we consider doppler primarily in terms of repulsive forces, radiation, sound, etc. No, ordinarily we think of Doppler as a change of frequency and not related to forces. Light is an exception since radiation pressure depends on frequency, but that's not too significant at the moment However doppler also operates in analogous terms for attractive forces such as gravitation, electrostatic, and magnetic forces except that effects are reversed. Consider two strong magnets on a table. They remain stationary as long as first order friction effects exceed magnetic attraction between them. However if one magnet is dragged away from the other at high speed the other magnet experiences an excess force of attraction causing it to move toward the moving magnet. Really? I haven't worked out the details but I haven't seen that effect. I suppose it might result from induction. The effect is pure doppler except in the case of attractive forces an increase in speed away increases wavelengths and strength of the attractive force. The same is true of all attractive forces operating through space. Increasing wavelengths of attractive forces increases the degree of attraction and decreasing wavelengths of attractive forces decreases attraction by amounts proportional to increases or decreases of speed in relation to the speed of propagation for the force, the speed of light. Imagine for a moment that the locus of attraction in the solar system suddenly moves. Do you imagine that planetary orbits would be unaffected? Changes in gravity are expected to propagate at c. If the sun suddenly moved away from the earth the earth would be tugged toward it by an amount linearly related to the speed of movement of the sun and having nothing to do with gravitational constants. No, it would be unaffected for about 500s then the force would start to diminish. I don't think you are talking of gravito-magnetic effects which would be very small if they existed in that configuration. And conversely if the sun suddenly moved toward the earth its attraction would be lessened by a comparable amount and the orbit of the earth extended as a result. Now in approaching the Pioneer anomaly all I did was show that the ratio between distance of expected travel and discrepancy in expected travel were almost identical (witnin 2%) of the speed of travel and the speed of light. I extrapolated the magnitudes over a year to conserve precision. In other words if we call the expected distance of travel D and the discrepancy in expected travel d, the speed of travel v and the speed of light c we find that D/d is almost exactly c/v. The problem there is that the discrepancy is a constant acceleration a_P hence d = 1/2 * a_P * t^2 while the speed is almost constant so D ~ v * t then D/d ~ (2 * v) / (a_P * t) snip Mercury I hope this explanation is a little clearer. Yes, it is better and hopefully my consternation is a little clearer too. v/c is constant and D increases linearly with time whereas d increases with the square of time because it is a constant acceleration. In other words Pioneer travels about 7 miles per second away from the sun and in doing so gravitation waves lengthen and their attractive intensity is experienced longer in each wave. (In this respect unlike repulsive waves like EM radiation, the effect of attraction increases in gravitation with longer waves and decreases with shorter waves.) And conversely the attraction of gravitation should decrease as the sun is approached. If it is increased when the craft is moving away from the Sun and decreased when moving towards, it is first order and the Sun's gravitational effect would be changed from a = GM/r^2 to a' = (1+v/c) * GM/r^2 The discrepancy would be a_P = v/c * GM/r^2 For Pioneer 10 that varies from 1.58*10^-13 m/s^2 at 40AU down to 6.77*10^-14 m/s^2 at 60AU. The anomaly is actually 8.74*10^-10 m/s^2 so your prediction is too small by a factor of about 5000 at the start and more than double that by the end of the period they studied. Your Clearly the Pioneer Anomaly is caused by what I call gravitational doppler. .... Not even close. Well, George, I'm not sure what the problem is here. Most of it was mine. I show the expected discrepancy in distance traveled by Pioneer is proportional to c/v and you tell me it isn't because you insist on relating it to gravitational acceleration instead of the actual anomaly. The discrepancy is in net distance traveled versus expected distance traveled and not in gravitational acceleration. I was trying to understand your description and guessed badly. You said the extra force was related to the speed ratio and since that is dimensionless you need to multiply it by an acceleration or speed to get it into dynamical units. The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. George Given that c/D = v/d Will d c = D v = Constant do it? d is quadratic D is linear v is linear Richard |
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Gravitational Doppler
On Tue, 25 Jul 2006 10:42:09 +0100, "George Dishman"
wrote: I'll coalesce my replies: George, for what it's worth in the past as these post/reply sequences lengthen I've found the reverse approach more useful, that is not to coalesce replies but to reply more or less in pieces to decrease the turnaround time for individual pieces. For my part since we're just conversing here I'd like to use that practice at least until we reach some consensus on what we're talking about. "Lester Zick" wrote in message .. . On Mon, 24 Jul 2006 22:38:04 +0100, "George Dishman" wrote: "Lester Zick" wrote in message ... On 24 Jul 2006 05:20:36 -0700, wrote: ... Lester, the original Anderson paper is he http://www.arxiv.org/abs/gr-qc/0104064 That's the abstract, there should be a PDF option on the page that gives you the full document (I have some preferences set so I get PDF by default, it might be an option for you). I've downloaded the pdf and am studying it. I won't try to comment in the interim except to minor unrelated stuff. So it'll be several hours to a day or more before I can comment further on the main topic. [. . .] Lester Zick ~v~~ |
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Gravitational Doppler
On Tue, 25 Jul 2006 10:42:09 +0100, "George Dishman"
wrote: I'll coalesce my replies: "Lester Zick" wrote in message .. . On Mon, 24 Jul 2006 22:38:04 +0100, "George Dishman" wrote: "Lester Zick" wrote in message ... On 24 Jul 2006 05:20:36 -0700, wrote: ... Lester, the original Anderson paper is he http://www.arxiv.org/abs/gr-qc/0104064 That's the abstract, there should be a PDF option on the page that gives you the full document (I have some preferences set so I get PDF by default, it might be an option for you). George, I appreciate the original reference but after several hours reviewing it am having considerable difficult finding out exactly where and how the acceleration was measured. I see numerous references to variances in acceleration and about everything else under the sun but nothing that shows what measured acceleration. For instance was it an accelerometer of some kind? Or was the measure of acceleration simply inferred from some other measurement? If you could tell me or at least point me to a page reference in the document it would be much appreciated. I'll try to reply to the balance of this post tomorrow. Thanks. Lester Zick ~v~~ |
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Gravitational Doppler
Lester Zick wrote: On Tue, 25 Jul 2006 10:42:09 +0100, "George Dishman" wrote: I'll coalesce my replies: "Lester Zick" wrote in message .. . On Mon, 24 Jul 2006 22:38:04 +0100, "George Dishman" wrote: "Lester Zick" wrote in message ... On 24 Jul 2006 05:20:36 -0700, wrote: ... Lester, the original Anderson paper is he http://www.arxiv.org/abs/gr-qc/0104064 That's the abstract, there should be a PDF option on the page that gives you the full document (I have some preferences set so I get PDF by default, it might be an option for you). George, I appreciate the original reference but after several hours reviewing it am having considerable difficult finding out exactly where and how the acceleration was measured. There is a lot in the paper. The basic technique is that a signal was sent to the craft, the uplink. When that was received, the craft was configured to lock its return (downlink) carrier to an exact multiple of the uplink frequency. The frequencies of the uplink and downlink were measured and recorded. The difference is the Doppler shift which indicates relative speed. The component due to the motion of the Earth is known and the remainder should indicate the motion of the craft. A 'best fit' of the craft motion to the measured Doppler is then produced using an optimum initial velocity and the known gravitational acceleration of all major solar system bodies. The Doppler due to that motion is then predicted. In theory of course it should be a perfect match to what was received since the trajectory was fitted to the data but it doesn't quite work. The reminder is plotted in Figure 8 and shows an apparent linearly increasing discrepancy in the velocity of the craft compared to that modelled, i.e. a constant acceleration. I see numerous references to variances in acceleration and about everything else under the sun but nothing that shows what measured acceleration. For instance was it an accelerometer of some kind? Or was the measure of acceleration simply inferred from some other measurement? If you could tell me or at least point me to a page reference in the document it would be much appreciated. Section II, D on page 5 gives a description of the overall communications system, Section III, A on page 8 describes the measurement equipment and Section III, B, 1 on page 9 explains the method. This gives speed and acceleration is inferred as explained above. Unfortunately, direct range measurement wasn't available from Pioneer 10 due to problems with the craft losing lock when it was attempted. George |
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Gravitational Doppler
Richard Saam wrote: wrote: Lester Zick wrote: .... The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. Given that c/D = v/d Will d c = D v = Constant do it? d is quadratic D is linear v is linear No, v is nearly constant. c/D ~ v/d is only approximately true in one particular year. George |
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Gravitational Doppler
On Tue, 25 Jul 2006 16:32:49 GMT, Richard Saam wrote:
wrote: Sci astro added, sci.math and comp.ai.p.. removed. Lester Zick wrote: On 24 Jul 2006 09:11:21 -0700, wrote: Lester Zick wrote: Gravitational Doppler ~v~~ We are well aware of gravitational lensing but there is another EM analog associated with Newtonian universal gravitation as well: gravitational doppler. In other words with latency extensions to Newtonian universal gravitation we can explain planetary orbital perihelion anomalies and calculate the Pioneer anomaly in simple, direct terms. To do this we only need to calculate Pioneer's velocity away from the sun as a fraction of the speed of light and recognize that the effect of the sun's gravitation will increase in proportion: (Numbers used here were drawn from a column 1 article in the L. A. Times of 12/21/2004 and are not exact) Yearly distance traveled by Pioneer = 219,000,000 miles Yearly discrepancy in distance = 8,000 miles Ratio = ~ 27,375 speed of light = 186,289 miles per second Yearly distance traveled by light in one year= 186,289 mi/sec x 1440 min/day x 60 sec/min x 365 days/yr Divided by yearly distance traveled by Pioneer Ratio = ~ 26,825 A difference between the two ratios of 2% (27375 - 26,825 / 27,375) QED ~v~~ I can't see any relation between the calculation above and the description below. Perhaps it wasn't as clear as I had hoped. I made an error in my calculation, I used km/s in one place and m/s in another, doh! That knocks a factor of 1000 out in the results so our numbers are much closer, sorry. At the time of publication Pioneer was traveling about 7 miles/sec (actually 6.9444 . . . according to my calculation. In January 1987 the speed was 7.984026 mile/sec In December 1994 the speed was 7.706486 mile/sec That number in relation to the speed of light produces a ratio around 27,000 The ratios above are 23332 and 24172 respectively so that's not bad given that you are using approximate speeds. or within 2% of the discrepancy in distance traveled. In other words the discrepancy in expected yearly distance of travel would be proportional to the ratio between the speed of travel and the speed of light taken as the speed of propagation for gravity. Now that's where we diverge. What do you mean by "the discrepancy in expected yearly distance of travel"? The anomaly is a constant acceleration so the discrepancy is speed increases each year and the discrepancy in distance is quadratic. Ordinarily we consider doppler primarily in terms of repulsive forces, radiation, sound, etc. No, ordinarily we think of Doppler as a change of frequency and not related to forces. Light is an exception since radiation pressure depends on frequency, but that's not too significant at the moment However doppler also operates in analogous terms for attractive forces such as gravitation, electrostatic, and magnetic forces except that effects are reversed. Consider two strong magnets on a table. They remain stationary as long as first order friction effects exceed magnetic attraction between them. However if one magnet is dragged away from the other at high speed the other magnet experiences an excess force of attraction causing it to move toward the moving magnet. Really? I haven't worked out the details but I haven't seen that effect. I suppose it might result from induction. The effect is pure doppler except in the case of attractive forces an increase in speed away increases wavelengths and strength of the attractive force. The same is true of all attractive forces operating through space. Increasing wavelengths of attractive forces increases the degree of attraction and decreasing wavelengths of attractive forces decreases attraction by amounts proportional to increases or decreases of speed in relation to the speed of propagation for the force, the speed of light. Imagine for a moment that the locus of attraction in the solar system suddenly moves. Do you imagine that planetary orbits would be unaffected? Changes in gravity are expected to propagate at c. If the sun suddenly moved away from the earth the earth would be tugged toward it by an amount linearly related to the speed of movement of the sun and having nothing to do with gravitational constants. No, it would be unaffected for about 500s then the force would start to diminish. I don't think you are talking of gravito-magnetic effects which would be very small if they existed in that configuration. And conversely if the sun suddenly moved toward the earth its attraction would be lessened by a comparable amount and the orbit of the earth extended as a result. Now in approaching the Pioneer anomaly all I did was show that the ratio between distance of expected travel and discrepancy in expected travel were almost identical (witnin 2%) of the speed of travel and the speed of light. I extrapolated the magnitudes over a year to conserve precision. In other words if we call the expected distance of travel D and the discrepancy in expected travel d, the speed of travel v and the speed of light c we find that D/d is almost exactly c/v. The problem there is that the discrepancy is a constant acceleration a_P hence d = 1/2 * a_P * t^2 while the speed is almost constant so D ~ v * t then D/d ~ (2 * v) / (a_P * t) snip Mercury I hope this explanation is a little clearer. Yes, it is better and hopefully my consternation is a little clearer too. v/c is constant and D increases linearly with time whereas d increases with the square of time because it is a constant acceleration. In other words Pioneer travels about 7 miles per second away from the sun and in doing so gravitation waves lengthen and their attractive intensity is experienced longer in each wave. (In this respect unlike repulsive waves like EM radiation, the effect of attraction increases in gravitation with longer waves and decreases with shorter waves.) And conversely the attraction of gravitation should decrease as the sun is approached. If it is increased when the craft is moving away from the Sun and decreased when moving towards, it is first order and the Sun's gravitational effect would be changed from a = GM/r^2 to a' = (1+v/c) * GM/r^2 The discrepancy would be a_P = v/c * GM/r^2 For Pioneer 10 that varies from 1.58*10^-13 m/s^2 at 40AU down to 6.77*10^-14 m/s^2 at 60AU. The anomaly is actually 8.74*10^-10 m/s^2 so your prediction is too small by a factor of about 5000 at the start and more than double that by the end of the period they studied. Your Clearly the Pioneer Anomaly is caused by what I call gravitational doppler. .... Not even close. Well, George, I'm not sure what the problem is here. Most of it was mine. I show the expected discrepancy in distance traveled by Pioneer is proportional to c/v and you tell me it isn't because you insist on relating it to gravitational acceleration instead of the actual anomaly. The discrepancy is in net distance traveled versus expected distance traveled and not in gravitational acceleration. I was trying to understand your description and guessed badly. You said the extra force was related to the speed ratio and since that is dimensionless you need to multiply it by an acceleration or speed to get it into dynamical units. The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. George Given that c/D = v/d Will d c = D v = Constant do it? d is quadratic D is linear v is linear My calculation doesn't use c or v directly. It uses D/d cited in the article and c*186289*1440*60*365/D. The result is accurate to 2%. These D and d values were rough approximations and subject to change over time but are assumed accurate in relation to each other for the period cited. Lester Zick ~v~~ |
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Gravitational Doppler
On 26 Jul 2006 02:18:05 -0700, "George Dishman"
wrote: Richard Saam wrote: wrote: Lester Zick wrote: ... The calculation is correct for the numbers given within the stated limits of precision. If you wish to relate the effect of gravitational doppler to actual gravitational acceleration you really have to take the basic calculation of the anomaly c/v and retrofit it to accommodate the correctness of that calculation. I'm not sure what you mean by that but the key question is how you relate the constant value of v/c and the linearly increasing D to the quadratic discrepancy d. Given that c/D = v/d Will d c = D v = Constant do it? d is quadratic D is linear v is linear No, v is nearly constant. c/D ~ v/d is only approximately true in one particular year. Disagree. The ratios themselves vary individually but their relationship to each other remains constant. It's how the effect is mechanized to begin with. More precisely the ratio v/c is what governs gravitational doppler and what causes the anomalous acceleration in Pioneer. Lester Zick ~v~~ |
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